Zinc is an essential nutrient and is necessary for the functioning of several metalloenzymes in humans and animals. Zinc deficiency is associated with anorexia, impaired immune, neural and reproductive functions. Zinc ions are present in neuronal cells. Due to its importance in human growth and development, human serum contains about 19 μM of this ion. Imbalanced homeostasis of Zn2+ may cause a variety of diseases. However, an excess of zinc compounds such as oxides, sulfates, sulfides, and chlorides are known to cause problems in the respiratory tract and lead to bronchopneumonia and pneumonitis, developmental defects, inflammatory reactions, and even death. Prolonged oral exposure to zinc may also reduce copper absorption. Estimates of the minimal risk levels of zinc range from 77-600 mg/m3 for inhalation, and is 0.3 mg/kg/day for oral exposure. There is a need for compounds that can detect Zn2+ and for methods for detecting Zn2+, for example in blood serum. Provided herein are compounds and methods suitable for detecting Zn2+ in a variety of samples.